The present invention relates to a mask for X-ray lithography used in the X-ray lithography technique, and a process for readily producing a mask for X-ray lithography having a high contrast for X-rays with a high accuracy.
The basic structure of the mask for X-ray lithography comprises a membrane 2 made of a material capable of transmitting soft X-rays and supported therearound by a ring 1, and a pattern 3 made of a material hardly capable of transmitting soft X-rays and formed on the membrane, as shown in FIG. 1. A pattern as mentioned above has heretofore been formed according to a process, as shown in FIG. 2(a), which comprises forming a multi-layer resist pattern 24 on a pattern material 23 capable of absorbing X-rays, such as gold, tantalum or tungsten, and subjecting this material 23 to dry processing with the multi-layer resist pattern 24 as a mask, or a process, as shown in FIG. 2(b), which comprises depositing gold 23' as an X-ray absorber in recessed portions of a multi-layer resist pattern 24' formed on a membrane by an electrolytic plating method (see A. R. Shimkunas, Solid State Technology, September 1984, p. 192-199). In either method, however, the manufacturing process is complicated with liability to cause a pattern defect and have a weak point for pattern accuracy, since the multi-layer process is involved.